Dec 11, 2011

Is electropolishing actually necessary given that a 1.0 or greater Cr/Fe ratio can be achieved by passivation alone? The short answer? If a 1.0 Cr/Fe ratio is all you are trying to achieve, no it is not. Now for the long answer. First, the 1.0 or greater Cr/Fe ratio indicated in the ASME BPE standard is a minimal requirement. The best passive and corrosion-resistant surfaces will have a Cr/Fe ratio in excess of 1.5/1, again achievable by passivation alone. The pharmaceutical industry, in most cases, requires a 15-25Ra value typically achieved through a mechanical polishing procedure. It is this procedure that, in my opinion, causes many of the problems experienced today with the formation of the “gray residue” and Class 1 rouge that has plagued end users for years.

Oct 11, 2011

This brief article will deal with a small part of a much bigger topic: surface finish. We will be looking at commercially available finish options and how they are measured. The surface finish of process systems components plays a very integral role in the cleanability and sterility of the system. The most commonly used unit for surface finish is...

Mar 23, 2011

For any project requiring alloy equipment, the best thing to do is look at the experience and expertise with the alloy. The first requirement for a fabricator should at a minimum be ASME Section VIII Div 1 certified for the manufacture of pressure vessels, even for equipment not requiring pressure service.

Mar 16, 2011

The most common corrosive species that has caused failures in chemical plant is the chloride ion. Chloride Stress Corrosion Cracking (CSCC) can occur in hot acid chloride solutions, sodium chloride/peroxide solutions, and seawater. Other neutral halides such as bromides, iodides and fluorides can also cause SCC of the 300 series stainless steels.

Feb 4, 2011

Question: If I purchase AL-6XN alloy (N08367) tubing or fittings to the ASTM A270-S2 specification, will they meet the low sulfur requirements? Many end users in pharmaceutical industry require the ASTM A270-S2 (pharmaceutical quality) tubing for their application. However, sulfur requirements are commonly misunderstood, and the ASTM A270 specification covers...

Dec 16, 2010

First, let me clarify. I am not proposing this discussion because I have any first-hand knowledge on this subject. I am certain that if Mr. Claus were to commission someone to construct new runners for his sleigh, he would do so under an alias—like Nick O. Las from The Jolly Old Elf Distribution Company, for instance. Anyway, where would Santa get money to pay for such a thing? He would have to barter. On that note...